Modelación de la distribución potencial del ratón andino Chilomys instans (Thomas, 1895)

Abstract

The Andean mouse Chilomys instans (Thomas 1895) is an endemic species of the northern Andes, little is known about its natural history, evolution, and ecology. This specie has been recorded in relatively well-preserved natural areas in high mountains, leading to the belief that it may be a group with high ecological requirements. The main objective of the study is to describe the potential niche distribution areas for this species, as well as to assess the geographical and altitudinal niche differentiation, identify the environmental variables influencing its suitable habitat, and generate some considerations regarding its conservation. The maximum entropy algorithm was applied to develop predictive models of maximum probability of habitat suitability. These models were produced using presence data and incorporating climatic variables and vegetation cover indices from remote sensors, implementing analyses for altitude, geography, and both aspects combined. An analysis of protected natural areas was conducted by overlaying vector layers of the protected areas system of Colombia and Ecuador with the general potential distribution to estimate the amount of territory the system is protecting for the species' suitable habitat. The models achieved AUC values greater than 0.9. For general model, different temperature variables were important in its construction. Elevation and isothermality influenced the development of models considering altitude. For geographical models, different aspects of temperature and leaf area produced particular potential distributions for each region. In Colombia, suitable habitat covers 186 territories in some management category, with Regional Natural Parks having the highest proportion (40%). In Ecuador, suitable habitat covers eleven protected areas, with a large part being National Parks (206,535.05 ha). The maximum probability of suitable habitat for C. instans encompasses high mountain habitats (> 2100 meters above sea level), from the south of Ecuador to occupying the three mountain ranges of Colombia in different proportions. However, models resulting from altitude and geographical differentiation analysis form distinct potential distributions, allowing the inference of a possible niche differentiation for Chilomys instans, in which altitude, topography, and geography converge in a possible isolation of potential populations initially distributed in the general model. National and Regional Natural Parks, as well as Flora and Fauna Sanctuaries, strictly protect the Andean Chilomys, given the conservation vocation for which they are safeguarded. On the other hand, a significant portion of Chilomys' suitable habitat overlaps with areas in management categories that allow sustainable use of biodiversity through anthropic activities such as agriculture, livestock, and mining, thus threatening the suitable habitat for this species to some extent.